Variable Undefined in Javascript after Explicit Assignment?

Question

For some reason my "initialLocation" variable is undefined when I make an alert on it, even though I explicitly assign it in the callback function for getCurrentPosition. Variable "initialLocation" is declared globally btw.

Maybe I'm not understanding this concept of closures?

var initialLocation;

if (navigator.geolocation) {
    geoLocationError = true;
    navigator.geolocation.getCurrentPosition(function(position) {
        initialLocation = new google.maps.LatLng(position.coords.latitude, position.coords.longitude);
        getFood();
        }, geoError);
    alert(initialLocation);
} else {
    geoLocationError = false;
    noGeolocation(geoLocationError);
}

Possible duplicate of [Why is my variable unaltered after I modify it inside of a function? - Asynchronous code reference](http://stackoverflow.com/questions/23667086/why-is-my-variable-unaltered-after-i-modify-it-inside-of-a-function-asynchron) — JJJ, Oct 25 '15 at 00:46
geolocation is asynchronous....you are trying to alert the value before it has been returned from location service — charlietfl, Oct 25 '15 at 00:54
Also, [use `var`](https://stackoverflow.com/questions/1470488/what-is-the-function-of-the-var-keyword-and-when-to-use-it-or-omit-it). — Félix Saparelli, Oct 25 '15 at 00:54

score 1 · Answer 1 · answered Oct 25 '15 at 05:29

1

navigator.geolocation.getCurrentPosition is asynchronous, so your alert is firing before initialLocation is set. You should place your alert inside the callback, just after you set initialLocation.

answered Oct 25 '15 at 05:29

whitfin

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Variable Undefined in Javascript after Explicit Assignment?

1 Answers1